Trends of significant operating events in assessing programmatic issues

This paper describes one part of the U. S. Nuclear Regulatory Commission's (NRC's) program for evaluating significant events and the process for identifying trends that may be indicative of programmatic weaknesses at operating nuclear power plants. A database management system was developed to permit analyses of significant operating events, events of potential safety significance, and certain reactor scrams. The analyses were based on events and problems reported by telephone to the NRC by licensees within hours of the events and, therefore, provided current operational data trend information. The regulatory requirements for reporting significant events, the screening criteria, and the process for identifying outliers for formal evaluation are described herein. This process contributed to an understanding of the underlying causes for events and problems. Examples are included of operating experience assessments that identified plants with a poor operating experience history that was attributable to procedural inadequacies, operator training deficiencies, inadequate root cause analysis, and inadequate control and planning of activities